Function DataFromTransaction

src/script/sign.cpp:447–512

Extracts signatures and scripts from incomplete scriptSigs. Please do not extend this, use PSBT instead

// Extracts signatures and scripts from incomplete scriptSigs. Please do not extend this, use PSBT instead
SignatureData DataFromTransaction(const CMutableTransaction& tx, unsigned int nIn, const CTxOut& txout)
{
    SignatureData data;
    assert(tx.vin.size() > nIn);
    data.scriptSig = tx.vin[nIn].scriptSig;
    data.scriptWitness = tx.witness.vtxinwit.size() > nIn ? tx.witness.vtxinwit[nIn].scriptWitness : CScriptWitness();
    Stacks stack(data);

    // Get signatures
    MutableTransactionSignatureChecker tx_checker(&tx, nIn, txout.nValue, MissingDataBehavior::FAIL);
    SignatureExtractorChecker extractor_checker(data, tx_checker);
    if (VerifyScript(data.scriptSig, txout.scriptPubKey, &data.scriptWitness, STANDARD_SCRIPT_VERIFY_FLAGS | SCRIPT_SIGHASH_RANGEPROOF, extractor_checker)) {
        data.complete = true;
        return data;
    }

    // Get scripts
    std::vector<std::vector<unsigned char>> solutions;
    TxoutType script_type = Solver(txout.scriptPubKey, solutions);
    SigVersion sigversion = SigVersion::BASE;
    CScript next_script = txout.scriptPubKey;

    if (script_type == TxoutType::SCRIPTHASH && !stack.script.empty() && !stack.script.back().empty()) {
        // Get the redeemScript
        CScript redeem_script(stack.script.back().begin(), stack.script.back().end());
        data.redeem_script = redeem_script;
        next_script = std::move(redeem_script);

        // Get redeemScript type
        script_type = Solver(next_script, solutions);
        stack.script.pop_back();
    }
    if (script_type == TxoutType::WITNESS_V0_SCRIPTHASH && !stack.witness.empty() && !stack.witness.back().empty()) {
        // Get the witnessScript
        CScript witness_script(stack.witness.back().begin(), stack.witness.back().end());
        data.witness_script = witness_script;
        next_script = std::move(witness_script);

        // Get witnessScript type
        script_type = Solver(next_script, solutions);
        stack.witness.pop_back();
        stack.script = std::move(stack.witness);
        stack.witness.clear();
        sigversion = SigVersion::WITNESS_V0;
    }
    // We enable SIGHASH_RANGEPROOF for signing.
    unsigned int flags = SCRIPT_SIGHASH_RANGEPROOF;
    if (script_type == TxoutType::MULTISIG && !stack.script.empty()) {
        // Build a map of pubkey -> signature by matching sigs to pubkeys:
        assert(solutions.size() > 1);
        unsigned int num_pubkeys = solutions.size()-2;
        unsigned int last_success_key = 0;
        for (const valtype& sig : stack.script) {
            for (unsigned int i = last_success_key; i < num_pubkeys; ++i) {
                const valtype& pubkey = solutions[i+1];
                // We either have a signature for this pubkey, or we have found a signature and it is valid
                if (data.signatures.count(CPubKey(pubkey).GetID()) || extractor_checker.CheckECDSASignature(sig, pubkey, next_script, sigversion, flags)) {
                    last_success_key = i + 1;